Impact driver



Jan. 30, 1968 A. 1.. VON TERSCH 3366,18?

' IMPACT DRIVER Filed Aug. 16, 1965 7 l4 l2 V /8 l y [620 V r w a a INVENTOQ ALFRED L. VON TEIQSCH United States Patent 3,366,187 IMPACT DRIVER Alfred L. Von Tersch, Clarinda, Iowa, assignor to Lisle Corporation, Clarinda, Iowa, a corporation of Iowa Filed Aug. 16, 1965, Ser. No. 479,714 Claims. (CI. 17.3-93.6)

ABSTRACT OF THE DISCLOSURE A tool for rotating bolts, nuts and the like for screwing or unscrewing them and driven by impact. Hammer blows on the head of the tool result in impact rotation either clockwise or counter clockwise depending on an initial adjustment when the tool is applied to the work, the head being manually rotated clockwise or subsequent clockwise rotation upon impact blows being delivered thereto, or counter clockwise for subsequent counter clockwise rotation upon impact blows being delivered thereto.

This invention relates to a hand tool of the impact driver type wherein axial movement of one part of the tool effected by striking it with a hammer results in rotary impact of another part of the tool, the tool thereby being adaptable for tightening nuts or screws and the like, and being reversible for loosening them.

One object of the invention is to provide a relatively rugged tool of the general character referred to wherein V-shaped projections and V-shaped seats coact with each other to effect the conversion of axial impact to rotation, the projections and seats being so interfitted as to have substantial area contact to minimize wearduring operation and prolong the service life of the tool.

Another object is to provide an impact driver which is readily reversible by the mere rotation of the body of the tool relative to a work-engaging element thereof in the direction that rotation resulting from axial impact is desired, an over-center detent means being provided to keep the tool adjusted for operation in either direction.

Still another object is to provide a head element adapted to be struck with a hammer or the like and thereby driven axially, and a work-engaging element operatively supported by the head element in such manner that it is rotated as a result of axial movement of the head element relative to the work-engaging element.

Still a further object is to provide the work-engaging element movable axially of the head element and a V- shaped projection and seat construction operable between the two elements to convert axial movement to rotary movement, resilient means being provided to effect a relationship between the V-shaped projections and the V- shaped seats such that the projections are normally only partially entered into the seats to provide for the necessary further entry of the projections into the seats for the conversion of axial movement to rotary movement.

An additional object is to provide means tending to rotate the work-engaging element so that the desired relationship of projections and seats are obtained in the form of a spring detent and a cam surface cooperating between the head element and the work-engaging element.

Another additional object is to provide the cam surface of dual character so that an over-center lobe is provided that coacts with the spring pressed detent to permit reversible adjustment of the tool for rotation in the desired direction in response to axial movement, always in the same direction and produced by a hammer, the cam surfaces being axially elongated to serve as limiting means in cooperation with the detent for axial movement of the work engaging element out of the head element under the action of the resilient means above referred to.

3,366,187 Patented Jan. 30, 1968 With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my impact driver, whereby the objects above contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in detail on the accompanying drawing, wherein:

FIG. 1 is a perspective view of an impact driver embodying my invention;

FIG. 2 is an enlarged vertical sectional view thereof showing the parts in normal position;

FIG. 3 is a sectional view similar to a portion of FIG. 2 showing the parts in the position they assume upon the tool being struck with a hammer and driven thereby to one axial limit;

FIG. 4 is a perspective view of part of the head element of my impact driver showing in phantom view a pair of V-shaped seats formed therein;

FIG. 5 is a perspective view of a work-engaging element of my impact driver showing V-shaped projections thereon;

FIG. 6 is a sectional view as taken on the line 66 of FIG. 4 through both elements of the tool shown in FIGS. 4 and 5 to show the normal cooperation of the V-shaped projections and seats for clockwise rotation;

FIG. 7 is a similar sectional view'showing the parts adjusted to a reversed position for counterclockwise rotation, and

FIG. 8 is a sectional view on the line 88 of FIG. 2 to show the detent and cam action involved in the reversing operation of the tool.

On the accompanying drawing I have used the reference character H to indicate a head element and W a work-engaging element of my impact driver. The head element H comprises a handle-like housing 10 and an insert 12, the two being rigidly connected together by a pin 14. The work-engaging element W has a shank 22 on which interchangeable sizes of wrench sockets may be positioned and held by a spring pressed ball detent 24 in the usual manner of socket wrench sets for rotating the screw or nut.

It will be noted in FIG. 2 that the lower half of the housing 10 is hollow to receive the insert 12, and also to rotatably and slidably receive the upper end of the work-engaging element W. The lower end of the insert 12 and the upper end of the element W are recessed as shown in FIG. 2 to receive a compression spring 16 as shown in FIG. 3. The spring has been shown dotted in FIG. 2 in order to more clearly show the cooperation of certain motion converting elements which will now be described.

The upper end of the work-engaging element W is provided with a pair of diametrically opposite V-shaped projections 18 and the lower end of the insert 12. is provided with a pair of diametrically opposite complementary V-shaped seats 20. The spring 16 in its normally expanded position will position the projections 18 and the seats 20 vertically with respect to each other as illustrated in FIG. 2. It will be noted the projections are partially entered into the seats, and means is provided for limiting the outward sliding movement of the element W relative to the element H as will hereinafter appear.

Referring to FIG. 6 when it is desirable to have the tool adjusted for clockwise or tightening operation on a screw or nut there should be a resilient tendency in the direction of the arrow (1 to keep the parts in the position shown. Accordingly, upon the head element H being struck and thereby driven downwardly according to the arrow 12 the resultant rotation will be in the direction of the arrow 0 and the final position of the parts will be as shown in FIG. 3the lower end of 12 engaging the upper end of W.

My tool can be adjusted for loosening a nut by providing a resilient tendency to rotate in the direction of arrow a in FIG. 7 so that axial movement of the head H, again in the direction of the arrow b will provide resultant rotation counterclockwise in the direction of arrow To provide the spring tendency desired for:

(1) Rotation in the direction of the arrows a and a in FIGS. 6 and 7.

(2) Limit the axial movement of the element W relative to the element H, and

(3) Provide an over-center detent for assuring adjustment being retained in either the direction for clockwise or counterclockwise rotation resulting from axial movement of the head element;

I provide (as shown in FIGS. 2, 3 and 8) a spring pressed detent ball 26, a C-spring 28 to provide the spring pressure therefor and a camming arrangement comprising a clockwise cam surface 30 and a counter-clockwise cam surface 32. Between the surfaces 3%) and 32 an over-center lobe 34 is provided by the corner between the surfaces 30 and 32. The ball 26 is slidable in a lateral hole 35 of the head element H and the C-spring 28 is confined due to its tendency to contract in an annular groove 38 of the head element H. The C-spring has a hole 29 to keep it centered on the ball 26.

As shown in FIG. 8 the detent ball 26 is pressing against the clockwise cam surface 30 in such manner as to tend to rotate the W0rkenglging element W counterclockwise according to the arrow a in both FIGS, 6 and 8. When the head element H (or housing is rota-ted counter-clockwise relative to the work-engaging element W in FIG. 8, the detent ball snaps over the lobe 34 and presses against the counter-clockwise cam surface 32 and tends to rotate the work-engaging element counter-clockwise.

Some changes may be made in the construction and arrangement of the parts of my impact driver without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which may reasonably be included within their scope.

I claim as my invention:

1. In an impact driver, a head element adapted to be struck and thereby driven axially, a work-engaging element operatively supported by said head element and movable axially thereof, one of said elements having a pair of diametrically opposite V-shaped projections and the other having a pair of diametrically opposite V-shaped seats, resilient means tending to slide said work-engaging element out of said head element, means to limit the sliding movement to a relation wherein said pair of projections are partially entered into said pair of seats, and means tending to rotate said work engaging element relative to said head element to a position with one side of each projection engaged with one side of each seat whereby axial movement of said element toward said work engaging element will result in rotation of said work engaging element, said last means comprising a radially biased detent carried by one of said elements and a circumferentially extending cam surface on the other of said elements and coacting with said detent.

2. An impact driver according to claim 1 wherein said cam surface is axially elongated and coacts with said detent to constitute said means to limit sliding movement.

3. In an impact driver, a head element adapted to be struck and thereby driven axially, a work-engaging element operatively supported by said head element and movable axially thereof, one of said elements having a pair of diametrically opposite V-shaped projections and the other having a pair of diametrically opposite V-shaped seats, resilient means tending to slide said work-engaging element out of said head element, means to limit the sliding movement to a relation wherein said pair of projections are partially entered into said pair of seats, and means tending to rotate said work engaging element relative to said head element to a position with one side of each projection engaged with one side of each seat whereby axial movement of said head element toward said work engaging element will result in rotation of said work engaging element, said means tending to rotate said workengaging element being reversible for engaging the opposite side of said projections with the opposite sides of said seats.

4. In an impact driver, a head element adapted to be struck and thereby driven axially, a work-engaging element operatively supported by said head element and movable axially thereof, one of said elements having a pair of diametrically opposite V-shaped projections and the other having a pair of diametrically opposite V-shaped seats, resilient means tending to slide said work-engaging element out of said head element, spring pressed detent and cam means tending to rotate said work-engaging element relative to said head element to a position with one side of said pair of projections engaged with one side of said pair of seats whereby axial movement of said head element toward said work engaging element will result in rotation of said work-engaging element, said cam means being elongated axially of said elements to limit sliding movement of said work-engaging element to a relation wherein said projections are partially entered into said seats.

5. An impact driver according to claim 4 wherein saizl cam means is of dual character and cooperates with said detent means to reverse the direction-of-rotation tendency of said work-engaging element relative to said head element for loosening a nut or the like when set at one adjustment and tightening it when set at the other adjustment.

References Cited UNITED STATES PATENTS 1,743,505 1/1930 Turgeon 8152.3 X 1,925,714 9/1933 Crist 17393.6 X 2,153,883 4/1939 Foster 173-936 X 2,543,441 2/1951- Crummey 81-52.35 X 3,139,933 7/1964 Golden 17393 OTHER REFERENCES Aviation Magazine, Pneumatically Pcrcussive Spiral Drive Unscrewer, November 1944, page 158.

FRED C. MATIERN, JR., Primary Examiner.

L. P. KESSLER, Assistant Examiner. 

